The present invention relates to a sealing system for a universal joint assembly and particularly to a one-piece sealing system.
Universal joint assemblies are well known in the art and in general include a cross member having a body portion having four trunnions extending outwardly from the body portion. Each of the trunnions generally includes an outer cylindrical friction surface extending outwardly from the body portion and an outer cylindrical journal surface extending outwardly from the friction surface and an arcuate surface interconnecting the journal surface and the friction surface. Each of the trunnions is provided with a bearing cup having an open end and an inner bearing surface. The bearing cups are disposed about the trunnion such that the inner bearing surface of the bearing cup is disposed coaxially about the outer cylindrical journal surface of the trunnion. Needle bearings are disposed between the inner bearing surface of the bearing cup and the outer journal surface of the trunnion for permitting rotation of the bearing cup relative to the trunnion.
One-piece and two-piece sealing systems for universal joint assemblies are well known in the art. Examples of two piece systems are shown in our aforesaid related application Ser. No. 079,727 and in U.S. Pat. Nos. 4,874,349, 5,588,915 and 5,716,277. In such systems a seal is provided at the open end of the bearing cup for engaging the surface of the trunnion and designed to keep the lubricant within the bearing cup. The second piece of the seal, sometimes referred to as the seal guard or dust guard, extends over the open end of the bearing cup and engages the trunnion friction surface to prevent the entry of dirt and other contaminants into the interior of the universal joint. Examples of one-piece sealing systems are shown in U.S. Pat. Nos. 3,200,615, 4,515,574, 4,530,675 and 4,861,315. While the sealing systems of the prior art have been satisfactory, in many respects they have left something to be desired in regard to simplicity of construction and effectiveness.